From the main bus, train, ferry or airport terminal go to the Diocletian palace and walk till the end of the south wall of the palace. Then turn right and cross the little square leaving the monument of Marko Marulic on your right side. Walk straight till you reach the main Old town square and then turn left. Walk for about 20m and then turn left through the little passage on which end on your left side are the stairs to the apartment.